Get VCT, or Vinyl Composition Tile.
There are essentially two kinds. The speckled tiles like you find in Wal-Mart or the solid colors like you find in my garage below.
The speckled tiles are half the price of the solid tiles, and are even more durable. But unless you want your garage to look like Wal-Mart, then go with the solid tiles.
The solid VCT tiles do not like oil, brake cleaner, etc. Caustic items and cleaners will ruin the finish. This does not mean you can't spill anything on the floors though. My floors love all of the Zaino products.
There is also modular flooring like that of Racedeck or the Costco brand you purchased. Both are plastic "lego-type" which you piece together to make a "floor." When I was doing my garage I priced it out and it actually came to the same price of the floor above (VCT). Only difference is the floor above included installation, where as with Racedeck you have to do it yourself.
I don't really see the purpose of Racedeck for permanent applications. Perhaps if you rent or are not sure how long you will live at your current home Racedeck would be a plausible option. Though if you know you are going to live where you are for quite some time than VCT IMO is a better choice.
The solid color VCT does make for a better showroom than workroom though. I have dropped some tools on the floor and whenever that happens damage will occur. Perhaps Racedeck would benefit here since you could easily replace the damaged tiles.
Also, if you consider VCT, make sure the garage floor is perfectly flat and was properly constructed. It has to be up the specifications of that of a floor in the room of an actual house (vapor barrier, etc.) Contractors like to skimp in these areas for garage floors. If the floor is not perfectly level the floor will develop little bumps on the surface. This has happened to me. It is not bad at all but it is something that you should consider.
Hope this helps. Here are some pics:
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